Method for forming disk, disk forming apparatus, data recording/reproducing method, data recording/reproducing apparatus, and disk capable of recording/reproducing data in high density

ABSTRACT

In a disk with a wobbling pregroove, data can be recorded in high density. A recording/reproducing apparatus for recording/reproducing data on/from a disk in which a sector is constituted by one arbitrary integer (F) of data frames, a cluster is constituted by another arbitrary integer (S) of the sectors, and data is recorded or reproduced in unit of the sector, or in unit of the cluster, is comprised of: reading means for reading a track number of an access point of the disk; storing means for storing a table about the track number and a zone, in which the following relationship is established, i.e., in two sets of the zones located adjacent to each other, data frame number of the zone per 1 rotation provided on an outer circumferential side of the disk is set to a value larger than data frame number of the zone per 1 rotation provided on an inner circumferential side of the disk by another arbitrary integer (K), the integer (K) being smaller than the integer (F); judging means for judging the zone belonging to the track number read by the reading means with reference to the table of the storing means; and generating means for generating a clock having a predetermined frequency in response to a judgment result the judging means.

BACKGROUND OF THE INVENTION

The present invention generally relates to a disk, a disk formingmethod, a disk forming apparatus, a recording/reproducing method, and arecording/reproducing apparatus. More specifically, the presentinvention is directed to a pregrooved disk, a pregrooved disk formingmethod, a pregrooved disk forming apparatus, a recording/reproducingmethod with using a pregrooved disk and a recording/reproducing apparatus with using a pregrooved disk, from which addresses can be readilydetected, and onto/from which data can be recorded/reproduced in highdensity.

To record data on disks, address information should be previouslyrecorded in such a manner that the data can be recorded on preselectedpositions of the disks. This address information may be recorded bywobbling a pregroove based on a frequency modulation wave obtained byfrequency-modulating the address information.

This address information wobbling process is usually executed in an MD(mini disk: trade mark), and a CDR (recordable compact disk).

That is, in such a disk, when a track for recording data is previouslyformed as a pregroove, a side wall of this pregroove is wobbled inaccordance with address information. Thus, an address can be read fromthe wobbling information (address information), so that data can berecorded on a desired position.

On the other hand, since the phase of the wobbling information (addressdata) is not coincident with the phase of the frequency modulation wavein the conventional disk, boundary portions of bits of address data canbe hardly discriminated, so that the address data may be erroneouslydetected.

Also, since the wobbling information is recorded in very low density,compared with the recording/reproducing information, when data isrecorded on a preselected sector on the basis of the wobblinginformation, the recording positions on the sectors are positionallyshifted every time the data is recorded. There is interference occurredin the continuous sectors so as to the recording positions on thesectors. Further, a buffer area must be formed between the successivesectors, on which no data is essentially recorded, in order to absorbjitter caused by eccentricity. If the interference between thesuccessive sectors is increased, then the size of this buffer area mustbe made large. As a result, such regions on which the data cannot beessentially recorded are increased. Eventually, the recording capacityof this disk would be lowered. As a consequence, there are such problemsthat the entire system would become very redundant, and the data can behardly recorded/reproduced at random in high density.

Under such a circumstance, in order to increase a storage capacity of adisk, this disk is not manufactured as a CAV (constant angular velocity)type disk whose angular velocity is made constant, but may bemanufactured as a CLV (constant linear velocity) type disk whose linearvelocity is made constant. However, rapid access operation cannot beachieved in such a CLV disk, as compared with a CAV disk.

Accordingly, a zone CAV disk is known as an intermediate disk existingbetween a CAV disk and a CLV disk. In this zone CAV disk, a datarecording region of the disk is segmented into a plurality of zones.This zone CAV disk is rotated whose angular velocity becomes constant.In the respective zones, one zone located on the outer circumferenceside owns a larger sector number per 1 track (1 rotation), as comparedwith a sector number per 1 track of another zone located on the innercircumference side. As a result, the recording density of the zone CAVdisk can be increased, as compared with that of the CAV disk, andfurthermore, rapid access operation can be achieved, as compared in theCLV disk.

However, very recently, there is a trend that an amount of codes usedfor correcting errors of data is increased in connection with data highdensity recording/reproducing techniques. As a result, even in such azone CAV disk, it is rather difficult to secure a sufficiently largestorage capacity.

OBJECTS AND SUMMARY OF THE INVENTION

The present invention has been made to solve the above-describedproblems, and therefore, can readily detect a clock and also canrecord/reproduce data in higher density.

To achieve the above-described object, a disk, according to an aspect ofthe present invention, is featured by that address data isbiphase-modulated; channel bit data obtained by biphase-modulating theaddress data is frequency-modulating a pregroove is wobbled based upon afrequency modulation wave obtained by frequency-modulating the channelbit data; and

a starting point and an end point of the channel bit are zero crosspoints of the frequency modulation wave.

Also, a disk forming apparatus, according to another aspect of theinvention, is featured by comprising: biphase modulating means forbiphase-modulating the address data; frequency modulating means forfrequency-modulating channel bit data obtained by biphase-modulatingaddress data by the biphase modulating means in such a manner that astarting point and an end point of the channel bit become zero crosspoints of a frequency modulation wave; and wobbling means for wobblingthe pregroove based upon the frequency modulation wave obtained byfrequency-modulating the channel bit data by the frequency modulatingmeans.

A recording/reproducing apparatus, according to another aspect of thepresent invention, is featured by comprising: recording/reproducingmeans for recording/reproducing information with respect to the disk;extracting means for extracting the address data from a reproductionoutput of the recording/reproducing means; and control means forcontrolling a position of the recording/reproducing means on the disk inresponse to the data extracted from the extracting means.

Further, a disk, according to another aspect of the present invention,is featured by that: a region for recording the data is segmented into aplurality of zones; and in two sets of the zones located adjacent toeach other, data frame number of the zone per 1 rotation provided on anouter circumferential side of the disk is set to a value larger thandata frame number of the zone per 1 rotation provided on an innercircumferential side of the disk by another arbitrary integer (K), theinteger (K) being smaller than the integer (F).

Also, a recording/reproducing apparatus, according to another aspect ofthe present invention, is featured by comprising: reading means forreading a track number of an access point of the disk; storing means forstoring a table about the track number and a zone, in which thefollowing relationship is established, i.e., in two sets of the zoneslocated adjacent to each other, data frame number of the zone per 1rotation provided on an outer circumferential side of the disk is set toa value larger than data frame number of the zone per 1 rotationprovided on an inner circumferential side of the disk by anotherarbitrary integer (K), the integer (K) being smaller than the integer(F); judging means for judging the zone belonging to the track numberread by the reading means with reference to the table of the storingmeans; and generating means for generating a clock having apredetermined frequency in response to a judgment result the judgingmeans.

Also, a disk forming method, according to another aspect of the presentinvention, is featured by that: the address data is biphase-modulated;channel bit data obtained by biphase-modulating the address data isfrequency-modulated in such a manner that a starting point and an endpoint of the channel bit constitute zero cross points of a frequencymodulation wave; and the pregroove is wobbled based upon the frequencymodulation wave obtained by frequency-modulating the channel bit data.

Then, a recording/reproducing method, according to a further aspect ofthe present invention, is featured by that: address data is extractedfrom the reproduction output of the disk; and an access point on thedisk is controlled in response to the extracted address data.

Also, a recording/reproducing method, according to a still furtheraspect of the present invention, is featured by that: a track number ofan access point of the disk is read; a table about the track number anda zone is stored in which the following relationship is established,i.e., in two sets of the zones located adjacent to each other, dataframe number of the zone per 1 rotation provided on an outercircumferential side of the disk is set to a value larger than dataframe number of the zone per 1 rotation provided on an innercircumferential side of the disk by another arbitrary integer (K), theinteger (K) being smaller than the integer (F); the zone belonging tothe track number read by the reading means is judged with reference tothe table of the storing means; and a clock having a predeterminedfrequency is generated in response to a judgment result the judgingmeans.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention may be understood from the detailed descriptionsto be read in conjunction with the accompanying drawings, in which:

FIG. 1 is an explanatory diagram for explaining such a condition that adisk according to the present invention is wobbled;

FIG. 2 illustrates a structural example of a wobbling address frame;

FIG. 3 represents a wobbled data frame structure;

FIG. 4 is a schematic block diagram for showing a circuit arrangement ofa wobbling signal generating circuit;

FIG. 5 shows one example of a biphase signal outputted from the biphasemodulating circuit 13 employed in the wobbling signal generating circuitof FIG. 4;

FIG. 6 indicates another example of a biphase signal outputted from thebiphase modulating circuit 13 employed in the wobbling signal generatingcircuit of FIG. 4;

FIG. 7 is an explanatory diagram for explaining a frequency modulationexecuted by an FM modulating circuit 15 of FIG. 4;

FIG. 8 schematically represents a frequency modulated signal outputtedfrom the FM modulating circuit 15 of FIG. 4;

FIG. 9 is a schematic block diagram for showing an internal arrangementof a recording apparatus for manufacturing disk 1 having a pregroove;

FIG. 10A through FIG. 10D are explanatory diagrams for explainingoperations of a synthesizing circuit 22;

FIG. 11 is a schematic block diagram for indicating an internalarrangement of an optical disk recording/reproducing apparatus to whicha recording/reproducing apparatus of the present invention is applied;

FIG. 12 is an explanatory diagram for explaining zones defined in adisk;

FIG. 13 is a flow chart for describing a clock switching processoperation performed in the optical disk recording/reproducing apparatusshown in FIG. 11;

FIG. 14 is an explanatory diagram for explaining a data format withrespect to 1 sector;

FIG. 15 is an explanatory diagram for explaining a structure of 32Kbytes data;

FIG. 16 is an explanatory diagram for explaining such a condition thatthe outer code of FIG. 15 is interleaved;

FIG. 17 is an explanatory diagram for explaining a structure of 32Kbytes block data; and

FIG. 18 schematically illustrates a structural example of a link area.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 schematically shows a structural example of an optical disk towhich a disk according to the present invention is applied. As shown inthis drawing, a pregroove 2 is previously formed in a disk (opticaldisk) 1 in a spiral form from an inner circumference toward an outercircumference. Alternatively, this pregroove 2 may be, of course, formedin a coaxial form.

A portion of this pregroove 2 is indicated in an enlarge form in FIG. 2.Right/left side walls of this pregroove 2 are wobbled in correspondencewith address information, and meandered in correspondence with afrequency modulated signal. A single track contains a plurality ofwobbling address frames.

FIG. 3 schematically represents a structure (format) of a wobblingaddress frame. As shown in FIG. 3, the wobbling address frame isarranged by 48 bits. First 4 bits of this wobbling address frame areused as a synchronization signal (Sync) indicative of a start of thiswobbling address frame. The succeeding 4 bits are used as a layer(Layer) for indicating which layer among a plurality of recordinglayers. The next 20 bits are used as a track address (track number).Further, the next 4 bits are employed so as to indicate a frame numberof an address frame. The succeeding 14 bits are used to express an errorcorrection code (CRC), on which an error correction code excluding thesynchronization signal (Sync) is recorded. The final 2 bits are saved asa future use.

As to a wobbling address frame, for instance, 8 frames are recorded per1 track (1 rotation) in a CAV disk manner such that a rotation angularspeed of a disk is constant. As a result, as the frame number of FIG. 3,for instance, values from "0" to "7" are recorded.

FIG. 4 schematically shows an internal arrangement of a wobbling signalgenerating circuit for generating a wobbling signal used to wobble thepregroove 2 in response to the address frame of the format indicated inFIG. 3. A generating circuit 11 of this wobbling signal generatingcircuit generates a signal having a frequency of 115.2 kHs. The signalgenerated from the generating circuit 11 is supplied to a dividingcircuit 12 so as to be divided by a value of 7.5. The divided signal issupplied to a biphase modulating circuit 13 as a biphase clock signalhaving a frequency of 15.36 kHz. Also, ADIP (Address In Pre-groove) dataequal to the frame format shown in FIG. 3 is supplied to this biphasemodulating circuit 13.

The biphase modulating circuit 13 biphase-modulates the biphase clocksupplied from the dividing circuit 12 based on the ADIP data (addressdata) supplied from a circuit (not shown), and then outputs a biphasesignal to an FM modulating circuit 15. Also, to this FM modulatingcircuit 15, a carrier having a frequency of 57.6 kHz is inputted whichis obtained by dividing the signal having the frequency of 115.2 kHzgenerated from the generating circuit 11 by a value of 2 by anotherdividing circuit 14. The FM modulating circuit 15 frequency-modulatesthe carrier entered from this dividing circuit 14 based upon the biphasesignal entered from the biphase modulating circuit 13, and then outputsthe resulting frequency modulation signal. The right/left side walls ofthe pregroove 2 of the disk 1 are formed (namely, wobbled) in responseto this frequency modulation signal derived from the FM modulatingcircuit 15.

FIG. 5 and FIG. 6 represent an example of the biphase signal outputtedfrom the biphase modulating circuit 13. In this embodiment, when thepreceding bit is equal to "0", as shown in FIG. 5, "11101000" isemployed as the sync pattern (Sync), whereas when the preceding bit isequal to "1", as indicated in FIG. 6, "00010111" is employed as the syncpattern which owns a reverse relationship with respect to thefirst-mentioned sync pattern shown in FIG. 5. It should be noted that"SYNC" corresponds to a unique pattern out of a rule, which does notappear in the modulation.

In the data bit (Data Bits) of the address data (ADIP data), "0" isbiphase-modulated to thereby be converted into channel bits (ChannelBits) of "11" (namely, when preceding channel bit is "0"), or "00"(namely, when preceding channel bit is "1"). Then, "1" isbiphase-modulated to thereby be converted into channel bits of "10"(namely, when preceding channel bit is "0"), or "01" (namely, whenpreceding channel bit is "1"). A decision for making how to convert thedata bit into any one of these two patterns depends upon the precedingcode. In other words, a waveform "Wave Form" shown in FIG. 5 and FIG. 6indicates such that the pattern of the channel bit "1" corresponds to ahigh-level signal, and the pattern of the channel bit "0" corresponds toa low-level signal. A selection is made of any one of these two patternsin order that this waveform becomes continuous.

In response to the biphase signal shown in FIG. 5 and FIG. 6, the FMmodulating circuit 15 frequency-modulating the carrier supplied from thedividing circuit 14 in such a manner shown in FIG. 7.

That is, when the channel bit data (biphase signal) is "0", the FMmodulating circuit 15 outputs a carrier of 3.5 waves during a timeperiod corresponding to a half length of 1 data bit. It should beunderstood that this carrier of 3.5 waves is commenced from either apositive half wave or a negative half wave.

To the contrary, when the channel bit data (biphase signal) is "1", theFM modulating circuit 15 outputs another carrier of 4 waves during atime period corresponding to a half length of 1 data bit. It should alsobe understood that this carrier of 4 waves is commenced from a positivehalf wave or a negative half wave.

Accordingly, when the channel data bit "00" corresponding to the data"0" is inputted, the FM modulating circuit 15 outputs a frequencymodulation wave of 7 waves (=3.5+3.5 waves) during a time periodcorresponding to a length of the data bit. When the channel bit 11 isinputted, the FM modulating circuit 15 outputs a frequency modulationwave of 8 waves (=4+4 waves). Also, when the channel data FM modulatingcircuit 15 outputs a frequency modulation wave of 7.5 waves(=4+3.5=3.5+4 waves).

Since the carrier having the frequency of 57.6 kHz inputted into the FMmodulating circuit 15 corresponds to the 7.5 waves, the FM modulatingcircuit produces this carrier of 7.5 waves, or such a frequencymodulation wave of 7 waves or 8 waves which is produced by shifting thecarrier of 7, waves by ±6.67% (=0.5/7.5) in response to the data.

As previously explained, a selection is made of the carrier startingfrom the positive half wave, or the carrier starting from the negativehalf wave, which corresponds to the channel data 0 or the channel 1,respectively, and is continued to the preceding signal.

FIG. 8 represents an example of the frequency modulation wave outputtedfrom the FM modulating circuit 15. In this example, it is assumed thatthe first data bit is "0", and the channel data bit thereof is "00".With respect to the first channel data bit "0", such a carrier of 3.5waves that a positive half wave is commenced from a starting point isselected. As a result, an end point of this carrier is terminated by apositive half wave. Accordingly, with respect to the next channel databit, such a carrier of 3.5 waves that a negative half wave is commencedis selected. As to the data bit "0", the frequency modulation wave of 7waves in total is outputted.

A data bit 1 (channel bit 10) is continued to this data bit "0". Sincethe carrier of 3.5 waves of the channel data bit corresponding to thepreceding data bit 0 is terminated at a negative half wave, a carriersuch that this carrier is commenced from a positive half wave isselected as the carrier of 4 waves of the first channel data bit "1"corresponding to the data bit 1. Since the 4 waves of this channel databit 1 is terminated at the negative half wave, as the 4 waves of thenext channel data bit "0", such a carrier that this carrier is commencedfrom a positive half wave is selected.

Similar to the above-described manner, carriers of 7.5 waves, 8 waves,and 7 waves are produced and outputted in such a manner that thesecarriers are continued at boundary portions (starting points and endpoints) of the data bits in correspondence with data bit "1"(namely,channel data bit 10), data bit "0" (namely, channel data bit 11), anddata bit "0" (namely, channel data bit 00).

As indicated in FIG. 8, in this embodiment, in any cases of the carrierof 7 waves, the carrier of 7.5 waves, and the carrier of 8 waves, thelength of the channel bit is selected to be equal to a length defined bymultiplying the wavelength of the carrier by an integer of 1/2. In otherwords, the channel bit length is equal to a length defined bymultiplying a 1/2 length of carrier (frequency modulation wave) of 7waves by 7, and also is equal to a length defined by multiplying a 1/2length of carrier (frequency modulation wave) of 8 waves by 8. Then, thechannel bit length is equal to a length defined by multiplying a 1/2length of carrier of 7.5 waves by 7 (when channel bit is 0), or by 8(when channel bit is 1).

Furthermore, in this embodiment, the boundary portion (starting point,or end point) of the biphase-modulated channel bit is set to become azero cross point of a frequency modulation wave. As a result, the phaseof the address data (channel bit data) is coincident with the phase ofthe frequency modulation wave, the boundary portion of this bit can beeasily discriminated. Thus, it is possible to prevent the address databit is erroneously detected. As a consequence, the address informationcan be precisely and easily reproduced.

Also, in this embodiment, a boundary portion (starting point and endpoint) of a data bit corresponds to an edge (zero cross point) of afrequency modulation wave. As a consequence, a clock may be producedwhile using the edge of the frequency modulation wave as a reference. Itshould be noted that as will be discussed later with reference to FIG.10, the clock is produced while using a clock sync mark as a referencein this embodiment.

FIG. 9 indicates an example of an internal arrangement of a recordingapparatus used to manufacture a disk 1 having a pregroove (namely, diskforming apparatus). The wobbling signal generating circuit 21 owns thearrangement as previously explained with reference to FIG. 4, andsupplies the frequency modulation signal outputted from the FMmodulating circuit 15 to a synthesizing circuit 22. A mark signalgenerating circuit 23 generates a clock sync mark signal atpredetermined timing, and then outputs this clock sync mark signal tothe synthesizing circuit 22. The synthesizing circuit 22 synthesizes thefrequency modulation signal outputted from the wobbling signalgenerating circuit 21 with the clock sync mark signal outputted from themark signal generating circuit 23, and then outputs the synthesizedsignal to a recording circuit 24.

Upon supply of the clock sync mark signal, the synthesizing circuit 22synthesizes a clock sync mark thereof (Fine Clock Mark) with the carriersupplied from the wobbling signal generating circuit 21 as shown in FIG.10. In such a case that recording/reproducing data is modulated by theEFM (eight-to-fourteen modulation) such as DVD, a length of the clocksync mark is equal to a length of 6 to 14 T (symbol "T" indicates lengthof bit call).

In other words, as indicated in FIG. 10A to FIG. 10D, when the channelbit data is equal to "00" (data 0), "11"(data 0), "10" (data 1), or "01"(data 1), such a clock sync mark having a frequency higher than themodulation frequency (57.6 kHz) of the address information issynthesized with the carrier at a zero cross point of a carrier of eachdata center (switching point of channel bit). This clock sync mark isrecorded every data bit, or every time a preselected number of data bitsis inputted.

As described above, the clock sync mark (Fine Clock Mark) is insertedinto the zero cross point of the wobbling frequency modulation wavecorresponding to a center of an address data bit (switching point ofchannel data bit), so that there is a small amplitude variation in theclock sync mark, and this amplitude variation can be easily detected.

That is to say, in such a case that when the channel data bit becomes 0,the carrier is frequency-modulated in the FM modulating circuit 15 insuch a manner that, for example, the frequency of this carrier isshifted by -5% from the center frequency, and when the channel data bitbecomes 1, the carrier is frequency-modulated in the FM modulatingcircuit 15 in such a manner that, for instance, the frequency of thiscarrier is shifted by +5% from the center frequency, the boundaryportion of the data bit, or the channel data bit is not coincident withthe zero cross point of the frequency modulation wave. As a result, thechannel data bit (otherwise, data bit) may be easily, erroneouslydetected. Also, the insertion position of the clock sync mark does notnecessarily constitute the zero cross point, but is superimposed on apoint having a predetermined amplitude value of the frequency modulationwave. As a result, the level of the clock sync mark is increased, ordecreased only by the amplitude value thereof, and therefore, this levelcan be hardly detected. In accordance with this embodiment, since theclock sync mark is always arranged at the zero cross point of thefrequency modulation wave, this clock sync mark can be readily detected(can be readily discriminated from the frequency modulation wave).

The recording circuit 24 controls an optical head 25 in response to thesignal supplied from the synthesizing circuit 22 to thereby producelaser light used to form a pregroove (containing a clock sync mark) in amother disk 26. A spindle motor 27 rotates the mother disk 26 in aconstant angular velocity (CAV).

That is, the frequency modulation signal generated from the wobblingsignal generating circuit 21 is synthesized with the clock sync marksignal outputted from the mark signal generating circuit 23 in thesynthesizing circuit 22, and the synthesized signal is entered into therecording circuit 24. The recording circuit 24 controls the optical head25 in response to the signal inputted from the synthesizing circuit 22to thereby produce the laser light. The laser light generated from theoptical head 25 is irradiated to the mother disk 26 rotated by thespindle motor 27 in the constant angular velocity.

The mother disk 26 is developed, and then a stamper is formed from thisdeveloped mother disk 26, and thereafter, a large number of replicas areformed as the disk 1 from this stamper. As a result, as previouslyexplained, the disk 1 in which the pregroove 2 having theabove-mentioned clock sync marks has been made is manufactured.

FIG. 11 indicates an example of an internal arrangement of an opticaldisk recording/reproducing apparatus for recording/reproducing data withrespect to the disk 1 manufactured in the above-described manner. Aspindle motor 31 is designed to rotate the disk 1 in the constantangular velocity (CAV). An optical head 32 irradiates laser light ontothe disk 1 so as to record the data on the disk 1 and reproduce datafrom light reflected from the optical disk 1. A recording/reproducingcircuit 33 reads data for 1 cluster when recording data entered from anapparatus (not shown) is temporarily stored in a memory 4, and the datain recording unit of 1 cluster (otherwise, data for 1 sector) are storedin this memory 34. Then, the recording/reproducing circuit 33 modulatesthe read data in accordance with a preselected modulation system tooutput the modulated data to the optical head 32. Also, therecording/reproducing circuit 33 demodulates the data entered from theoptical head 32 in a proper manner to output the demodulated data toanother apparatus (not shown either).

An address generating/reading circuit 35 generates a data address(sector address) (see FIG. 14) to be recorded on a track (withinpregroove 2) under control by a control circuit 38, and then outputs thedata address to the recording/reproducing circuit 33. Therecording/reproducing circuit 33 adds this data address to the recordingdata supplied from the apparatus (not shown), and then outputs the addeddata to the optical head 32. When the address data is contained in thedata reproduced from the track of the disk 1 by the optical head 32, therecording/reproducing circuit 33 separates this address data from thereproduced data, and then outputs this separated address data to theaddress generating/reading circuit 35. The address generating/readingcircuit 35 outputs the read address to the control circuit 38.

A mark detecting circuit 36 detects a component corresponding to theclock sync mark from an RF signal reproduced/outputted by/from theoptical head 32. A frame address detecting circuit 37 reads the addressinformation (track number and frame number of FIG. 3) contained in thewobbling signal out from the RF signal outputted from the optical head32, and then supplies the read address information to a cluster counter46 and the control circuit 38.

A mark period detecting circuit 40 judges a periodical characteristic ofa detection pulse which is derived when the mark detecting circuit 36detects the clock sync mark. In other words, since the clock sync markis generated in a constant time period, the mark period detectingcircuit 40 judges as to whether or not the detection pulse inputted fromthe mark detecting circuit 36 is equal to this detection pulse generatedin a constant time period. If this detection pulse is equal to thedetection pulse generated in a constant time period, then the markperiod detecting circuit 40 generates another pulse synchronized withthis detection pulse and then supplies this generated pulse to a phasecomparator 42 of a PLL circuit 41 provided in a post stage. When thedetection pulse is entered in a constant time period, the mark perioddetecting circuit 40 generates a quasi-pulse at preselected timing inorder that the PLL circuit 41 provided at the post stage is not lockedto the erroneous phase.

The PLL circuit 41 includes a low-pass filter (LPF) 43, a voltagecontrolled oscillator (VCO) 44, and a frequency divider 45 in additionto the phase comparator 42. The phase comparator 42 compares the inputfrom the mark period detecting circuit 40 with the input from thefrequency divider 45 to output a phase error. The low-pass filter 43filters the phase error signal derived from the phase comparator 42 tooutput the filtered phase signal to the VCO 44. The VCO 44 produces aclock of a phase corresponding to the output from the low-pass filter 43to thereby output this clock to the frequency divider 45. The frequencydivider 45 frequency-divides the clock entered from the VCO 44 based ona predetermined values (a value designated by the control circuit 38),and then outputs the frequency-divided result of the phase comparator42.

The clock outputted from the VCO 44 is supplied to the respectivecircuits, and also to a cluster counter 46. The cluster counter 46counts the number of clocks outputted from the VCO 44 on the basis ofthe frame address supplied from the frame address detecting circuit 37.When the count value reaches a preset value (namely, value correspondingto a length of one cluster), the cluster counter 46 produces a clusterstart pulse and supplies this cluster start pulse to the control circuit38.

A thread motor 39 transports the optical head 32 to a predeterminedtrack position of the disk 1 under control of the control circuit 38.The control circuit 38 controls the spindle motor 31 so as to rotate thedisk 1 in a constant angular velocity (CAV).

In a ROM 47, a table is stored which may define a correspondencerelationship between the track number (see FIG. 3) in the address frameand a zone for segmenting a data recording region of the disk 1.

In other words, as indicated in FIG. 12, the control circuit 38 segmentsthe disk 1 into a plurality of zones ((m+2) pieces of zones from the0-th zone to the (m+1)th zone in this embodiment), andrecords/reproduces the data with respect to the segmented zones.Assuming now that the number (quantity) of data frames per 1 track inthe 0-th zone is "n" (this data frame is different from the addressframe as explained with reference to FIG. 3, but corresponds to the unitof data block), the data frame number per 1 track in the subsequentfirst zone is equal to "n+16". Similarly, in one zone on the outercircumferential side, the data frame number thereof is increased by 16,as compared with the adjoining zone on the inter circumferential side.In the (m +1)th zone, i.e., the outermost circumferential zone, thetotal data frame number becomes n+16×(m+1).

The 0-th zone is switched into the first zone with the same line densityas the line density of the innermost circumference of the 0-th zone(zeroth zone) from a radial position where a capacity of (n+16) framesis obtained. Similarly, in the m-th zone, it is set to the m-th zonefrom a radial position where a capacity of (n+16×m) frames is obtainedwith the same line density as the line density of the innermostcircumference in the 0-th zone.

For instance, assuming now that a radial range of the disk 1 from 24 mmto 58 mm is defined as a recording/reproducing area, a track pitch ofthis disk 1 is 0.87 μm, and the line density is 0.38 μm/bit, therecording/reproducing area is segmented into 48 pieces of zones. In the0-th zone whose disk radial is 24 mm, the frame density becomes 528frames per 1 track. When the zone is incremented by 1,16 frames per 1track are increased.

As will be described later, in this embodiment, since one sector isconstructed of 24 frames (data frames), the number (=16) of framesincremented every zone is set to be a smaller value than the number(=24) of frames for constituting this one sector. As a consequence, itis possible to constitute a large number of zones in more fine unit, andthus, the capacity of the disk 1 can be increased.

Subsequently, operations of the optical disk recording/reproducingapparatus shown in FIG. 11 will now be described. In this case,operations when data is recorded are explained. The optical head 32irradiates the laser light onto the optical disk 1, and outputs the RFsignal obtained from the reflection light of the optical disk 1. Theframe address detecting circuit 37 reads out the wobbling information(address information) from this RF signal, and then outputs this readwobbling information to the control circuit 38 and also to the clustercounter 46. Also, this read wobbling information is supplied to the markdetecting circuit 36 from which the clock sync mark is detected. Then,this clock sync mark is supplied to the mark period detecting circuit40.

The mark period detecting circuit 40 judges the periodicalcharacteristic of the clock sync mark, and produces a predeterminedpulse in accordance with the judgment result, which will then besupplied to the PLL circuit 41. The PLL circuit 41 produces the clock(recording clock ) in synchronism with this pulse, and supplies thisrecording clock to the cluster counter 46.

The control circuit 38, can detect the position of the reference clocksync mark in 1 track (1 rotation) from the frame address (frame number)supplied from the frame address detecting circuit 37. While the clocksync mark is used as a reference, which is detected from, for example, aframe of a frame number 0 (address frame), the control circuit 38 canaccess to an arbitrary position on the track based on the count value ofthe recording clock.

When the control circuit 38 accesses to an arbitrary position on thetrack in the above-described manner, the control circuit 38 is furtherrequired to make such a judgment that which zone, this access pointbelongs to. Also, the control circuit 38 must control the VCO 44 toproduce the clock having the frequency corresponding to this zone.Accordingly, the control circuit 38 furthermore executes a clockswitching process operation described in a flow chart of FIG. 13.

At a first step S1 of this flow chart, the control circuit 38 reads outthe track number from the frame address of the access point outputted bythe frame address detecting circuit 37. Then, at a step S2, the zonecorresponding to the track number read at the step S1 is read from thetable stored in the ROM 47. As previously explained, the table of theROM 47 previously stores such a corresponding relationship, i.e., thetracks having the respective numbers belong to any of the zones from the0-th zone to the (m+1)th zone.

Therefore, at a step S3, a judgment is made as to whether or not thepresently read track number belongs to a new zone different from the sofar accessed zone. When it is so judged that this presently read tracknumber belongs to the new zone, the clock switching process operation isadvanced to a step S4. At this step S4, the control circuit 38 controlsthe frequency divider 45 to set a frequency dividing rate therein, whichcorresponds to this new zone. As a consequence, the recording clockshaving the different frequencies from each other with respect to each ofthese zones are outputted from the VCO 44.

To the contrary, when it is judged at the step S3 that the present zoneis not equal to the new zone, the process at the step S4 is skipped. Inother words, the frequency dividing rate of the frequency divider 45 isnot changed, but is kept.

Next, a format of recording data will now be explained. As previouslydescribed, data is recorded in unit of 1 cluster (32 Kbytes) in thisembodiment. This cluster is arranged as follows:

In other words, as shown in FIG. 14, 2 Kbytes (2048 bytes)-data isextracted as data for 1 sector, and 16-byte overhead is added to thisextracted 2 Kbyte-data. This overhead contains a sector address (namely,address generated, or read by address generating/reading circuit 35 ofFIG. 11), and an error detecting code for detecting an error, and so on.

As represented in FIG. 15, this 2064 byte-data (i.e., =2048 bytes +16bytes) is set as 12×172 (=2064) byte-data. Then, 16 pieces of data for 1sector are collected to constitute 192 (=12×16)×172 byte-data. To this192×172 byte-data, a 10 byte-inner code (PI) and a 16 byte-outer code(PO) are added as a parity with respect to each byte along the lateraldirection and the longitudinal direction.

Furthermore, among the 208 (=192+16)×182 (=172+10) byte-data blocked inthe above-described manner, each of the 16×182 byte-outer codes (PO) isadded to 16 pieces of 12×182 byte-sector data (numbered from "0" to"15"), and interleaved. The blocked data is segmented into 16 pieces of1×182 byte-data. Then, 13 (=12+1)×182 byte-data corresponding to datafor 1 sector.

In addition, the 208×182 byte-data indicated in FIG. 16 is subdividedinto two data along the longitudinal direction. 1 frame is constitutedby 91 byte-data, as shown in FIG. 17. The 208×182 byte-data is set as(208×2 frame) data. A 2 byte-frame sync signal (FS) is further added toa head of the 91 byte-frame data. As a result, as shown in FIG. 17, thedata for 1 frame becomes 93 byte-data in total, namely 208 (93×2)byte-block data. This block data constitutes data for 1 cluster. A sizeof a real data portion excluding an overhead portion thereof becomes 32kbytes (=2048×16/1024 Kbytes).

In other words, 1 cluster is constructed of 16 sectors, and 1 sector isconstituted by 24 frames.

These data are recorded on the disk 1 in unit of cluster. In thisrecording operation, as illustrated in FIG. 18, the control circuit 38arranges a link area between one cluster and the subsequent cluster.

As shown in FIG. 18, the link area is arranged by four frames dataframes). Similar to the case of the data area contained in cluster), 1frame data is constructed of 93 bytes. A 2 byte-frame sync signal(FS=Frame Sync) is arranged at a head of each frame.

In the link area, 86 byte data and 3-frame data are added in front of 32Kbyte-data block (cluster) to be recorded. The 20 byte-head data amongthe 86 byte-data is used as a prebuffer (Prebuffer) and an ALPC(Automatic Laser Power Control). The prebuffer is such a buffer forabsorbing a positional shift about a starting position of a clustercaused by jitter. The ALPC corresponds to an area for setting recordpower, into which data used to set laser light power during the readingoperation, or the reproducing operation to a preselected value isstored.

Slice/PLL are arranged in the subsequent 66 byte-area. The Slice is suchdata for setting a time constant used to process reproducing data toobtain binary data, and the PLL is such data for reproducing a clock.

Slice/PLL are arranged in each of the subsequent 2 frames. In a final 1frame, Slice/PLL are arranged in an 83 byte-head area, a sync signal(Sync) is arranged in the next 4 byte-area, and a last 4 byte-area isreserved for a future use (Reserve).

After the 32 Kbyte (cluster)-data block, a 2 byte-frame sync signal, a 1byte-postamble (Postamble), and a 8 byte-postbuffer (Postbuffer) areformed. In the postamble, such data is recorded which controls the marklength of the final data to return the signal polarity. The postbuffercorresponds to a buffer area for absorbing the jitter caused byeccentricity. In case of such a ideal case that there is completely nojitter, the 4 byte postbuffers among the 8 byte postbuffer areoverlapped, and the prebuffer and the ALPC of the next cluster arerecorded.

This link area is applied to a ROM disk, so that both the ROM disk andthe RAM disk may be formed with a common format. In this alternativecase, in the ROM disk, information may be recorded in the postbuffer,the prebuffer, and the ALPC of the link area. For example, an address isentered, so that the address information probability may by increased.

It should be noted that the lengths (byte numbers) of the respectiveregions described in the above-described embodiment are merelyexemplified, and therefore may be selected to be proper values.

Alternatively, the present invention may be applied to other cases, forinstance, data may be recorded, or reproduced on/from disks other thanan optical disk.

What is claimed is:
 1. A disk in which a track for recording data ispreviously formed as a pregroove, and said pregroove is wobbled inaccordance with address data, wherein:said address data isbiphase-modulated; channel bit data obtained by biphase-modulating theaddress data is frequency-modulated; said pregroove is wobbled basedupon a frequency modulation wave obtained by frequency-modulating thechannel bit data; and a starting point and an end point of said channelbit are zero cross points of said frequency modulation wave.
 2. A diskas claimed in claim 1 wherein:a length of said channel bit is equal to alength defined by multiplying a half wavelength of said frequencymodulation wave by an integer.
 3. A disk as claimed in claim 1 wherein:async mark is recorded on a zero cross point of said frequency modulationwave of a center of bits of said address data.
 4. A disk as claimed inclaim 3 wherein:said sync mark is a frequency higher than that of saidfrequency modulation wave.
 5. A disk as claimed in claim 1 wherein:saidaddress data is recorded on the disk under such a condition that arotation angular velocity of the disk becomes constant.
 6. A diskforming apparatus for forming a disk in which a track for recording datais previously formed as a pregroove, and said pregroove is wobbled inaccordance with address data, comprising:biphase modulating means forbiphase-modulating said address data; frequency modulating means forfrequency-modulating channel bit data obtained by biphase-modulatingsaid address data by said biphase modulating means in such a manner thata starting point and an end point of said channel bit become zero crosspoints of a frequency modulation wave; and wobbling means for wobblingsaid pregroove based upon said frequency modulation wave obtained byfrequency-modulating the channel bit data by said frequency modulatingmeans.
 7. A recording/reproducing apparatus for recording/reproducinginformation with respect to a disk made such that a track for recordingdata is previously formed as a pregroove, and said pregroove is wobbledin accordance with address data;said address data is biphase-modulated;channel bit data obtained from the biphase modulation isfrequency-modulated in such a manner that a starting point and an endpoint of said channel bit become zero cross points of a frequencymodulation wave; and said pregroove is wobbled by said frequencymodulation wave obtained from the frequency modulation, comprising:recording/reproducing means for recording/reproducing information withrespect to said disk; extracting means for extracting said address datafrom a reproduction output of said recording/reproducing means; andcontrol means for controlling a position of said recording/reproducingmeans on said disk in response to said data extracted from saidextracting means.
 8. A disk forming method for forming a disk, in whicha track for recording data is previously formed as a pregroove, and saidpregroove is wobbled in accordance with address data, wherein:saidaddress data is biphase-modulated; channel bit data obtained bybiphase-modulating the address data is frequency-modulated in such amanner that a starting point and an end point of said channel bitconstitute zero cross points of a frequency modulation wave; and saidpregroove is wobbled based upon said frequency modulation wave obtainedby frequency-modulating the channel bit data.
 9. A recording/reproducingmethod for recording/reproducing information with respect to such a diskthat a track for recording data is previously formed as a pregroove, andsaid pregroove is wobbled in accordance with address data, wherein:saidaddress data is biphase-modulated; channel bit data obtained bybiphase-modulating the address data is frequency-modulated in such amanner that a starting point and an end point of said channel bitconstitute zero cross points of a frequency modulation wave; and saidpregroove is wobbled based upon said frequency modulation wave obtainedby frequency-modulating the channel bit data, wherein: said address datais extracted from the reproduction output of said disk; and an accesspoint on said disk is controlled in response to said extracted addressdata.